Educational device

ABSTRACT

A simple, durable, inexpensive educational device for demonstrating the variables affecting heat production especially adapted for use by educational institutions below the college level is described. The device comprises a base member, a chamber for containing a supply of a liquid, means for securing the chamber to the base member, a thermally conductive metal insert and a thermometer. Included are means on the chamber for holding the metal insert and the thermometer in contact with a supply of liquid. Means are included for rubbing the metal insert.

United States "Patent [191 Lawlor et al.

[ EDUCATIONALDEVICE 75] Inventors: John E. Lawlor, Tappan, N.Y.; JohnSgombick, Ramsey, NJ.

[73] Assignee: Xerox Corporation, Stamford,

Conn.

[22] Filed: Nov. 22, 1972 [21] Appl. No.: 308,864

52 user ..35/19R s1 lnt.Cl. ..G09b23/16 [58] Field of Seareh.....;.....35/19 R [56] References Cited OTHER PUBLICATIONS Welch ScientificApparatus and Supplies Catalog 1965, page 161, MechanicalEquivalent-of-Heat Apparatus, Cavendish Form.

[ Mar. 19, 1974 Primary E.rar'niner l-larland S. Skogquist- ABSTRACT Asimple, durable, inexpensive educational device for demonstrating thevariables affecting heat production especially adapted for use byeducational institutions below the college level is described. Thedevice comprises a base member, a chamber for containing a supply of aliquid, means for securing the chamber to the base member, a thermallyconductive metal insert and a thermometer. Included are means on thechamber for holding the metal insert and the thermometer in contact witha supply of liquid. Means are included for rubbing the metal insert.

12 Claims, 3 Drawing Figures PATENTEUMARISIQM 3'797'132 SHEET 2 OF 2EDUCATIONAL DEVICE BACKGROUND OF THE DISCLOSURE I. Field of theInvention i This invention relates to educational devices, and moreparticularly to an educational device for demonstrating variablesaffecting heat productiomreferred to as a heat generating device. I

II. Description of the Prior Art I i "As an educational device, the heatgenerating device is a fundamental tool for the teaching of manyprinciples in learning institutions below the college level. Forexample, a student is given an opportunity to perform I 'and 2,745,195.The devices described therein, al-

though satisfactory in some respects, do not possess the combinedadvantages of being relatively inexpensive, rugged, easilyassembled andrelatively portablewhen compared to the novel and advantageous device ofthe present invention.

SUMMARY OF THE INVENTION It is therefore an object of the presentinvention to overcome the disadvantages stated hereinabove and toprovide an educational device which is simpler, more durable, lessexpensive, more easily assembled and still more pleasing from a designviewpoint than prior art devices, and otherwise more suitablefor use inlearning institutions below the college level.

It is a further object of the present invention to provide aneducational device for demonstrating the variables affecting heatproduction.

It is a further object of this invention to provide an educationaldevice which is compact when assembled.

It is a further object of this invention to provide an educationaldevice which is quickly disassembled for easy storage in a very smallspace.

It is a further object of this invention to provide an educationaldevice which does not require a single grommet, screw, bolt, rivet orsimilar fastening type connection.

It is still a-further object of this invention to provide an educationaldevice which, in addition to its educa-. tional features and manymechanical advantages, possesses a pleasing design.

The foregoing objects and others are accomplished in accordance with thepresent invention by providing an educational device comprising a basemember, a chamber for containing a supply of a liquid, means forsecuring the chamber to the base member, a thermally conductive metalinsert, a thermometer, and means on the chamber for holding the metalinsert and the thermometer in contact with a supply of liquid.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of theinvention, as well as other objects and further features thereof,reference tional device; and

FIG. 3 is a perspective view of an educational device in accordance withthe invention affixed to a supporting surface.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. l,theeducational device in accordance with the features of this invention isshown to comprise a base member 10 designed in a manner which permitsvarious parts of the device to be easily secured thereto. Releasablysecured to the base member 10 is a chamber 11 which is designed tocontain a supply of a liquid. Means in the form of a locking flange 12extending from the bottom portionof the chamber 11, and a locking device13, are used to firmly secure thechamber to the base member 10. Athermally conductive metal insert 14 is employed for the purpose oftransmitting heat to the supply of liquid in the chamber by mechanicalmeans. Also provided is a thermometer 1-5 which is used to allow thestudent to visually record any difference in the temperature of theliquid. Means in the form'of two separate chambers 16 and 17 located inchamber 11, as best shown in FIG. 2, firmly hold the metal insert 14 andthe thermometer 15 in contact with a supply of liquid in chamber 11.

The educational device described herein can be mounted to a supportsurface 20 as shown in FIG. 3, such as a table, by any of numeroussecuring or mounting means such as, for example, clamps, etc. Onespecific example of means for mounting the base member 10 to supportingsurface 20 is shown as vacuum mounting means 21. By employing suchmounting or securing means, the device is thereby made portable anddemountable for movement from location'to location as the need arises.When employing the vacuummounting means, channels (not shown) which areformed in the base member -10 engage extending shoulders 30 (noteFIG. 1) of an upper surface of a housing 31 of the vacuum mounting means21. A tab segment 32 of the base member'10 extends through a window 33in the vacuum mounting means 21 and engages the window frame for lockingthe educational device to the vacuum .mount. The educational device canbe demounted by depressing the tab 32 and simultaneously withdrawing thebase 10 from the vaccum mount 21. The educational device is therefore.conveniently demountable from the surface 20 by rotation of a lever arm40 which operates to release the vacuum. A vacuum mount of this type isshown and described in detail and is claimed in corresponding US. Pat.application .Ser. No. 144,934 filed May 19, 1971 and which is assignedto the assigne e-of this invention. I

In assembling the educational device, the vacuum mount 21 is positionednear the edge of a support surface 20, secured thereto, and the basemember 10 is connected to the vacuum mount in a locked relationship inthe manner described above. As shown in FIG. 1 the chamber 11, includinglocking flange 12 and tabs 18 all extending from the bottom portion ofthe chamber, can be attached to the base member by inserting the lockingflange through the opening 19 and by simultaneously inserting tabs 18through openings 25. Openings l9-and 25 are positioned on the uppersurface of the base member as shown in FIG. 1. Locking device 13 whichincludes two substantially parallel arm-like members 50 is then slippedover the substantially circular flange portion 51 of locking flange 12.The arm-like members are spaced from each other at a distance which issufficient to permit insertion of the elongated tubular portion 53 oflocking flange 12 therebetween. An illustration of the chamber 11 firmlysecured to base member 10 by this locking means is shown in FIG. 2.

Chamber 11 is designed to comprise an internal receptacle divided intoconnected compartments or cells 16 and 17 for containing a liquid suchas, for example, water. Compartment 17 is designed such that thermometerfits firmly therein resting on bottom portion 60; Thermometer 15preferably comprises a typical glass bulb thermometer 61 encased in aplastic rectangular housing 62 which includes on its face portion atemperature scale such as, for example, in degrees Centigrade.

Firmly inserted within compartment 16 is metal insert 14 comprisingsupport means 63 upon which rests conductive metal strip 64. Supportmeans 63 comprises semicircular wall portion 65 connected by member 66.The metal strip is preferably formed of a strip of heat conductive metalformed into a U-shape such that the top portion is supported by member66 while the two leg members of the U-shape extends into the bottomportion of compartment 16 as shown in FIG. 2. The width of the metalinsert is preferably sufficient to extend substantially the completedistance between wall portions 65. Compartment 16 includes an upstandingtab (not shown) which inserts within a hole (not shown) in member 66 tofirmly support metal insert 14 within the compartment.

The thermally conductive r netal strip 64 is formed of any suitablemetal or alloy which is a good conductor of heat. Examples of some ofthe preferred metals and alloys which are eminently suitable includecopper, brass, bronze, etc.

In accordance with the present invention, various suitable materials maybe used for manufacturing the various parts of the educational deviceherein described. However, in accordance with the preferred embodimentsof this invention, the base member 10, chamber 11 including lockingflange 12, locking device 13 and support means 63 are all preferablyconstructed of plastic.

The educational device of the present invention is designed to allow thestudent to produce heat in such a way that the heat can be measured. Forexample, the student can produce heat mechanically and measure the heatproduced by placing both the metal strip 64 and the thermometer 15 incontact with a measured quantity of a liquid such as, for example, twomilliliters of water. The liquid, which can be any of numerous types ofliquids, is poured into chamber-1 l and thereby fills both compartments16 and 17 to the desired level. The amount of liquid added to chamber 11can vary, but should be sufficient to insure that the bulb portion ofthermometer 15 and the bottom portions of metal strip 64 are immersedtherein. The U-shape of metal strip 64 enables the student to heat itmechanically as shown in FIG. 3 by rubbing the metal strip with a strap70. The strap can be formed of numerous materials such as, for example,leather. However, in accordance with the present invention other meanscan be used to rub the metal insert and heat it mechanically such as,for example, emery cloth, sandpaper, shoelaces, a clothesline, etc. Uponrubbing the metal strip, the

metal conducts the heat formed by the rubbing to the liquid, and theliquids rise in temperature is shown on the thermometer 15. Thetemperature rise is a measure of the heat produced mechanically byrubbing and this can be observed by the student.

The educational device of the present invention is designed to permitconsiderable freedom for the students to identify and change variousvariables and test several hypotheses of the above described experimentsuch as, for example, the following:

1. The faster the student moves the strap back and forth, the greaterthe heat produced;

2. The harder the student pulls down on the strap (as it is moved backand forth), the greater the heat produced;

3. The longer the stroke, the greater the heat produced;

4. The greater the number of strokes, the greater the heat produced;

5. Two straps side by side will produce more heat than a single strap.(The wider the strap, the greater the heat.) v

6. If the student varies both the length of the stroke and the speed ofthe stroke but keeps the product length of stroke X speed of strokeconstant, the amount of heat produced will remain constant;

7. The greater the amount of liquid used, the longer the time requiredto increase the temperature.

The educational device described herein can also be used to measure heatfrom a chemical reaction. In this activity the students can produce heatin several ways, e.g., by dissolving a salt in water, and by mixing anacid with a base. In regard to the first of these experiments, it shouldbe noted that most salts produce temperature changes when they aredissolved in water. Sometimes the effect is that the mixture gets coolerand sometimes hotter. Therefore, students have the opportunity to observe both the increase and decrease of temperature due to a chemicalreaction. Here, for example, hydrated copper sulfate'when dissolved inwater in chamber 11 can be used to produce a small decrease intemperature as recorded on thermometer 15. On the other hand, anhydrouscopper sulfate can be used to illustrate an increase in temperature ofthe solution as it dissolves. Regarding the second of these experiments,when a solution of an acid reacts with a base, the final temperature ofthemixture is usually higher than the initial temperature of the twosolutions. Here students can observe the changes in temperature bymixing, for example, acids such as dilute acetic acid (vinegar) orcitric acid solution with household ammonia.

In both of the above described experiments there is considerable freedomfor the students to identify and change various variables. For example,in the first experiment, the mass of the salt and the volume of watercan be changed. In the second experiment the amount of acid, the amountof base and the amount of water added to the acid and base mixture canbe identified and changed to obtain either smaller or larger changes intemperature.

Various types of experiments which can be performed by students usingthe educational device of this invention are explained in detail inScience A Process Approach/Part G, Variables Affecting Heat Productionpublished by the American Association for the Advancement of Science.

While we have illustrated and described a particular embodiment of ourinvention, it will be understood that various modifications may be madetherein without departing from the spirit of the invention and the scopeof the appended claims.

We claim:

1; An educational device comprising a base member; a chamber forcontaining a supply of a liquid; means for securing said chamber to saidbase member, a thermally conductive metal insert, a thermometer, andmeans on said chamber for holding said metal insert and said thermometerin contact with said liquid.

' 2. An educational device according to claim 1 further including meansfor rubbing said metal insert.

3. An educational device according to claim 2 wherein said rubbing meansis an elongated leather strap.

4. An educational device according to claim 1 wherein said liquid iswater.

5. An educational device according to claim 1 wherein said means forsecuring said chamber to said base member comprises a locking flangeextending from said chamber and a locking device releasably secured tosaid locking flange.

6. An educational device according to claim 5 wherein said lockingflange includes an elongated tubular portion connected at one end to abottom portion of said chamber'and a substantially circular flange at 9.An educational device according to claim 8 wherein said base memberincludes openings for insertion of each of said tabs and said flange.

10. An educational device according to claim 1 wherein said means forholding said metal insert and said thermometer comprises two connectedcompartments within said chamber.

11. An educational device according to claim 1 wherein said metal insertincludes a support means and a U-shaped strip of metal releasablysecured to said support means.

12. An educational device according to claim 1 wherein said metal isbrass.

1. An educational device comprising a base member; a chamber forcontaining a supply of a liquid; means for securing said chamber to saidbase member, a thermally conductive metal insert, a thermometer, andmeans on said chamber for holding said metal insert and said thermometerin contact with said liquid.
 2. An educational device according to claim1 further including means for rubbing said metal insert.
 3. Aneducational device according to claim 2 wherein said rubbing means is anelongated leather strap.
 4. An educational device according to claim 1wherein said liquid is water.
 5. An educational device according toclaim 1 wherein said means for securing said chamber to said base membercomprises a locking flange extending from said chamber and a lockingdevice releasably secured to said locking flange.
 6. An educationaldevice according to claim 5 wherein said locking flange includes anelongated tubular portion connected at one end to a bottom portion ofsaid chamber and a substantially circular flange at the opposite endthereof.
 7. An educational device according to claim 5 wherein saidlocking device includes two substantially parallel arm-like membersconnected at one end thereof, said arm-like members being spaced fromeach other at a distance sufficient to permit insertion of said lockingflange therebetween.
 8. An educational device according to claim 5wherein the bottom portion of said chamber includes said locking flangeand two tabs extending therefrom.
 9. An educational device according toclaim 8 wherein said base member includes openings for insertion of eachof said tabs and said flange.
 10. An educational device according toclaim 1 wherein said means for holding said metal insert and saidthermometer comprises two connected compartments within said chamber.11. An educational device according to claim 1 wherein said metal insertincludes a support means and a U-shaped strip of metal releasablysecured to said support means.
 12. An educational device according toclaim 1 wherein said metal is brass.